1. Field of the Invention
This invention relates to multipurpose oil-soluble additives for lubricating oils having utility to impart to an oil when incorporated therein an improved viscosity index and/or metal-wear protection and/or sludge dispersancy and/or a lowered pour point. More particularly, this invention relates to additives for lubricating oils which comprise the reaction products: of nitrogen compounds having one or more amino groups; of oxygen compounds having one or more hydroxyl, epoxide or ether groups; and/or, sulfur compounds; and/or hydrogen; with alternating interpolymers of monomers comprising: (A) one or more polar monomers; (B) one or more monoolefins or diolefins; and (C) a monomer similar to (A) and (B) but containing a reactive group that reacts with said nitrogen, oxygen or sulfur compounds or hydrogen.
2. Prior Art
Extensive work on the preparation of nitrogen derivatives of polymeric materials and on the preparation of alternating copolymers of polar and olefinic monomers has been reported in the patent literature. For example:
U.S. Pat. No. 3,316,177 discloses the reaction of a polyamine with the reaction product of maleic anhydride with an oxidized copolymer of ethylene and propylene, as a sludge dispersant in fuels and lubricants.
U.S. Pat. No. 3,404,091 describes the preparation of nitrogen containing polymers, useful as sludge dispersants and viscosity index improvers, by grafting polar monomers such as acrylonitrile onto hydroperoxidized copolymers of ethylene and propylene.
U.S. Pat. No. 3,404,092 describes the preparation of polymeric viscosity index improvers containing urethane groups by the reaction of a hydroxylated copolymer of ethylene and propylene with an isocyanate.
U.S. Pat. No. 3,687,905 describes the preparation of additives for fuels and lubricants by the reaction of maleic anhydride with a degraded, oxidized copolymer of ethylene and propylene, followed by reaction with a polyamine.
British Pat. No. 983,040 describes the preparation of detergent additives for lubricants by the reaction of a polyamine with a long-chain monocarboxylic acid prepared by the oxidation of an olefin polymer.
British Pat. No. 1,172,818 describes the preparation of additives for lube oils by the condensation of an amine with an ozonized polymer.
Copolymers of alkyl acrylates with halogen-containing monomers are old in the art. For example, copolymers of ethyl acrylate with from 2.5 to 5% of 2-chloroethyl acrylate or 2-chloroethyl vinyl ether have been available commercially as Lactoprene EV since 1944. Similar copolymers of alkyl acrylates with vinyl chloroacetates are disclosed in U.S. Pat. No. 3,201,373.
U.S. Pat. Nos. 3,183,217; 3,278,503; and 3,426,005 describe the preparation of alternating interpolymers from polar and olefinic monomers using Lewis acid-peroxide catalyst systems.
Numerous other patents disclose alternating interpolymers utilizing olefinic monomers including:
U.S. Pat. No. 3,578,636 discloses the preparation of alternating interpolymers of an olefin or halogenated olefin with an acrylic acid or haloalkylester of acrylic acid;
U.S. Pat. No. 3,629,215 discloses alternating interpolymers of alpha olefins, halo-olefins and alpha or beta substituted acrylic compounds; and,
U.S. Pat. No. 3,635,924 describes the preparation of copolymers from halo-olefins and acrylic compounds; (also U.S. Pat. Nos. 3,578,636; 3,629,215; 3,635,924; 3,637,611; 3,647,771; 3,700,647; 3,700,648; 3,752,788; 3,814,735).
U.S. Pat. No. 3,856,685 discloses interpolymers of propylene and/or isobutylene with an acrylic compound which have utility as a viscosity index improver for lubricating compositions.
Relevant pending patent application filed by common assignee to this application include:
U.S. patent application Ser. No. 383,093 filed July 7, 1973 now U.S. Pat. No. 3,926,925 discloses interpolymers containing one or more branched monoolefins or vinyl ethers, a polar monomer such as an alkyl acrylate and a minor amount of a derivative of fumaric acid or maleic acid;
U.S. patent application Ser. No. 452,969 filed Mar. 20, 1974 abandoned in favor of a C.I.P. application now issued as U.S. Pat. No. 3,959,225 discloses interpolymers of an olefin and/or halo-olefin, an acrylic or alicyclic ester of acrylic acid and a minor amount of a conjugated diolefin; and,
U.S. patent application Ser. No. 459,865 filed Apr. 11, 1974 now abandoned in favor of C.I.P. application Ser. No. 650,974 discloses interpolymers of monoolefins, acrylic acid esters and halomethylated aromatic vinyl compounds. This application has now issued as U.S. Pat. No. 4,026,809.